Superconducting fault current limiters are well known in the art and rely on the quench of a length of superconductor and its rise in impendence in response to a fault current so as to limit the size of the fault current. The rise in impedance limits the fault current which can flow. Hence, SFCLs can be used alone or with other switch gear which is sized to switch the much reduced fault current. Such SFCLs are used (and being proposed for use) in a number of industries, for example, within national electricity supply grids.
However, prior art SFCLs are generally hardwired into electrical networks making maintenance and exchange of the units difficult and time consuming, or have electrical conductors passing through a wall of a cryostat to allow connection, thereby making the systems thermally lossy.
The present invention seeks to provide an SFCL which can be more easily maintained.